Apparatus for transferring seedlings from plant trays

ABSTRACT

The present invention relates to an automatic transplanter. More specifically, the invention relates to a mechanism for transferring seedlings or plants from plant trays or flats in which they have been grown or propagated onto a conveyor for delivering to means for effecting transplanting into a field.

This is a continuation application of U.S. application Ser. No.08/537,918, filed Nov. 1, 1995, now U.S. Pat. No. 5,644,999, issued Jul.8, 1997, which is a U.S. National Phase Application of InternationalApplication No. PCT/US94/08783, filed Aug. 2, 1994.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an automatic transplanter. Morespecifically, the invention relates to a mechanism for transferringseedlings or plants from plant trays or flats ("trays" and "flats" areused interchangeably in the art and in the application) in which theyhave been grown or propagated onto a conveyor for delivering to meansfor effecting transplanting into a field.

2. Related Art

Related prior art transplanters have included indexing mechanisms thatengage on the ends and sides of trays containing seedlings or whichengage a single contact point on the back of such trays. Therefore,these previous transplanters require a mechanism for ejecting theseedlings from the trays that is separate from the indexing mechanism.An inherent disadvantage of these previous transplanters is thefrequency of misalignment between the seedling ejection apparatus andthe rows of seedlings in a particular tray. This misalignment resultsfrom variations in the center-to-center distance between rows ofseedlings in a tray and the center-to-center distance between the lastrow of seedlings on one tray and the first row of seedlings on a secondsucceeding tray being fed into position for ejection of the seedlings.Previous transplanters have relied on gravity for the feeding of asecond tray into contact with the indexing mechanism after a first trayhas been completely emptied. Consequently, soil or foliage trappedbetween the two trays often causes significant misalignment of theseedling ejection mechanism with the rows of seedlings in the tray; suchmisalignment can result in a multitude of malfunctions, none of whichare beneficial.

Previous transplanters have employed feed mechanisms which require theuse of hard plastic trays rather than trays made from materials such asexpanded polystyrene which is of insufficient strength to withstand theforces exerted by such feed mechanisms because of the relatively softnature of the expanded polystyrene. However, expanded polystyrene traysare desirable to use because of their light weight and lower cost.

SUMMARY OF THE INVENTION

The transplanter of the present invention is adapted to be mounted on asupporting vehicle such as a tractor capable of movement along a row andhaving planting means which receives seedling plants from the presentinvention and inserts them in the soil in conventional manner.Disadvantages of earlier transplanters are overcome by providing anindexing mechanism and a seedling or plug ejection mechanism which arepositively located relative to each other and relative to a common datumsurface on the plant tray. An expanded polystyrene plant tray of thetype used with the present invention is of rectangular configurationhaving a longer longitudinal dimension and a shorter transversedimension. Each plant tray includes a plurality of plant or seedlingcells for containing plugs of growing medium arranged in a matrix ofspaced perpendicular longitudinal and transverse rows of the seedlingcells. The seedling cells each have a centrally located drain hole onthe bottom surface of the plant tray. These plant trays have drivegrooves located between adjacent longitudinal rows of cells across asubstantial part of the bottom surface of the tray (which is oriented ina vertical plane when in the apparatus of the present invention).

The indexing mechanism of the transplanter according to the presentinvention includes a rotary indexing drum adapted to engage with thedrive grooves of the tray and actuation means arranged to index theindexing drum and hence move the plant tray in sequential steps along apredetermined vertical path perpendicular to the longitudinal rows ofseedling cells. An entire longitudinal row of plants is ejected from thetray during each dwell of the indexing drum. In the preferred embodimentthe drive grooves comprise parallel indexing grooves in the bottomsurface of the plant tray located on either side of the longitudinalrows of cells so that a drive groove is provided between eachlongitudinal row of cells. The drive grooves extend upwardly from thebottom surface of the plant tray, opposite from the top side of theplant tray from which the seedlings extend.

The rotary indexing drum comprises a driven hollow cylindrical rollhaving a plurality of parallel longitudinally extending cylindrical rodswhich define its outer extent and each of which is parallel to the axisof rotation of the hollow cylindrical roll so as to be drivinglyengageable with the drive grooves of the tray. This configurationmaximizes the contact area between the drive means and the grooves andspreads the resulting mechanical forces created by the indexing rollover a large area of plant tray surface. Therefore, the pressure loadthat must be withstood by the plant tray during indexing is spread overa large area and reduced so that materials such as expanded polystyrenecan be used without damage to the tray surface.

Thus, the preferred embodiment of the indexing drum includes a pluralityof indexing rods arranged in spaced, parallel relationship around thecircumference of a circle to form a cylindrical indexing drum having aninterior cavity and a central axis along which the drum rotates. Theindexing drum is rotatably supported by rollers mounted on a drumsupport frame and located at each end of the drum to engage the outerperiphery of the drum to maintain proper radial and linear positioningof the drum at all times. The drum support frame also allows for quickand efficient replacement of an indexing drum in order to accommodateplant trays of different dimensions. The support frame also supports aplug ejection mechanism which comprises a linear row of plug ejectingpins mounted on a pin mounting beam that is parallel to the axis of theindexing drum and which is positioned within the interior cavity of theindexing drum. The plug ejecting pins can be moved into contact with thelower ends of the soil plugs of a longitudinal row of seedlings locatedin between two adjacent indexing grooves of a tray so as to eject theseedlings outwardly from the tray for deposit onto a conveyer whichcarries the seedlings to conventional planting means which plants themin a row as the supporting vehicle moves along the row.

The plant tray of the present invention also includes a centrallylocated transverse alignment groove in the bottom surface of the planttray which is perpendicular to the indexing grooves and is configured tomate with the outer circumference of a circular mid ring on the indexingdrum. This alignment groove provides a datum surface in addition to thedatum surfaces provided by the indexing grooves for maintaining theplant tray in proper position relative to the axis of the indexing drumand the plug ejection mechanism.

In the preferred embodiment, the plant trays are oriented in a verticalplane and the indexing mechanism is adapted to index the plant traysdownwardly in a vertically configured tray support assembly or loadingframe so that plants or seedlings are ejected horizontally from thecells of the plant trays. The above mentioned datum surfaces provided bythe transverse alignment groove and the longitudinal indexing grooves onthe bottom of the plant tray ensure accurate alignment between plugejector pins and the drain holes located in the bottom center of eachcell. The plug ejection mechanism is mounted to the indexing drumsupport frame and includes a pin mounting beam positioned parallel tothe center axis of the indexing drum. The plug ejecting pins aresupported by the pin mounting beam for a consistent axial entry into thebottom of each plant cell of the plant tray and for consequent accuratepositioning in alignment with the center line of each row of plugs to beejected from the plant tray.

The entire mechanism consisting of the hollow indexing drum, the plugejection mechanism and a power source for rotating the indexing drum andactivating the plug ejection mechanism is arranged to be a unit, and isattached as a unit to the plant tray loading frame by a pivotallymounted indexing drum frame and a retention device which allows forquick assembly and disassembly. Different plant tray sizes or planttrays with a different number of plant cells can be easily accommodatedby changing the indexing drum and/or the plug ejection mechanism.

A greater biassing force is required than gravity alone to accuratelyand consistently move plant trays down from their initial loadingposition in the loading frame to be ready for positive engagement andlocation on the indexing drum. This force is provided by one or moredown loader drums similar in construction to the indexing drum andlocated on separate pivotal support frames vertically above the indexingdrum.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is better understood by reading the following DetailedDescription of the Preferred Embodiments with reference to theaccompanying drawing figures, in which like reference numerals refer tolike elements throughout, and in which:

FIG. 1 is a front elevation of the preferred embodiment of theinvention.

FIG. 1A is a left side elevation view of the preferred embodiment;

FIG. 1B is a partial rear elevation view taken in the direction ofarrows B--B in FIG. 1A.

FIG. 1C is a view taken in the direction of arrows C--C in FIG. 1B.

FIG. 1D is a view similar to FIG. 1A but illustrating the support frameand index drum in a deactivated position for permitting loading or rapidunloading of plant flats from the apparatus.

FIG. 1E is a right side elevation view of the preferred embodimentshowing the pneumatic cylinder and return spring mounted on the downloader drum support frame.

FIG. 2 is a vertical sectional view illustrating the relationship of theupper down loader drum to the vertical guide means for the plant flats.

FIG. 2A is a front elevation view of the transplanter showing an upperplant tray being urged vertically downwardly by the down loader drum andcontacting a lower tray which is engaged with the indexing drum and fromwhich plants are being ejected.

FIG. 2B is a front elevation view of the transplanter similar to FIG. 2Ashowing the relative positions of an upper and lower plant tray at thepoint when pneumatic locking cylinders are activated to grasp the upperplant tray prior to discharge of the lower empty tray.

FIG. 3 is a bottom plan view of a plant flat or tray employed with thepresent invention.

FIG. 3A is a front elevation view of the plant flat of FIG. 3.

FIG. 3B is an end elevation of the plant flat as viewed from line 3B--3Bof FIG. 3A.

FIG. 4 is a rear perspective view of the preferred embodiment of thedown loader drums employed in the invention and the associated drivemeans employed therewith.

FIG. 5 is a side elevation view of the preferred embodiment of the downloader drum engaged with the indexing grooves on the bottom surface of aplant tray.

FIG. 5A illustrates the manner in which down loader drums are mounted.

FIG. 6 is a side elevation view of the indexing drum and its associatedsupport rollers.

FIG. 7 is a front elevation view of one end of the indexing drum and itssupport rollers.

FIG. 8 is a perspective view of a further embodiment of the indexingdrum.

FIG. 9 is an enlarged front elevation view of a portion of the mid ringand indexing rods of the indexing drum of FIG. 8.

FIG. 10 is a front elevation view of a portion of the transplanterincluding the indexing drum of FIG. 10 along with means for indexing thedrum and means for locking the indexing drum in successive indexpositions.

FIG. 11 is a side elevation view of the components shown in FIG. 10 witha pawl member engaged with the indexing drum in a first position priorto the initiation of an indexing movement of the indexing drum.

FIG. 12 is a side elevation view of the pawl member of FIG. 11 in asecond position immediately following the initiation of an indexingmovement.

FIG. 13 is a side elevation view of the pawl member of FIG. 11 in athird position subsequent to the FIG. 12 position.

FIG. 14 is a side elevation view of the pawl member of FIG. 11 in afourth position subsequent to its FIG. 13 position.

FIG. 15 is a side elevation partial section view of the indexing drumand the preferred plug ejection mechanism illustrating the manner ofejecting plants from a plant tray.

FIG. 16 is a side elevation view of the indexing drum and plug ejectionmechanism similar to FIG. 16 but employing different plug ejection pins.

FIG. 17 is a perspective view of a plant foliage separator comb assemblyused for separating and downwardly guiding plants ejected from the planttray.

FIG. 18 is a perspective view of a second embodiment of the plugejection mechanism.

FIG. 19 is a perspective view of a third embodiment of the plug ejectionmechanism.

FIG. 20 is a perspective view of a fourth embodiment of the plugejection mechanism.

FIG. 21 is a front elevation view of a second embodiment of the conveyerbelt;

FIG. 22 is a front elevation view similar to FIG. 21 with the secondembodiment of the conveyer belt in a lowered position.

FIG. 23 is a perspective view of a second embodiment of a down loaderdrum mounted on a pivotal support frame.

FIG. 24 is a side elevation view of the second embodiment down loaderdrum of FIG. 23 engaging with the indexing grooves on the lower surfaceof a plant tray.

FIG. 25 is a front elevation view, partially in cross section, of athird embodiment of the down loader drum having rotatable down loaderbars.

FIG. 26 is a side elevation view of the rotatable down loader barsapproaching engagement with the indexing grooves on the lower surface ofa plant tray.

FIG. 27 is a side elevation view of a rotatable down loader bar engagedwith an indexing groove on the back surface of a plant tray.

FIG. 28 is a side elevation view of an upper and lower plant traycontacting each other along one edge.

FIG. 29 is an enlarged side elevation view of the indexing drum and plugejection mechanism and upper and lower plant trays being fed intoposition for ejection of seedlings.

FIG. 30 is a side elevation view similar to FIG. 29 showing the upperplant tray locked in position while the lower plant tray is indexeddownward.

FIG. 31 is a side elevation view similar to FIG. 29 showing the upperplant tray being downloaded after emptying of the lower plant tray.

FIG. 32 is a side elevation view similar to FIG. 29 showing the upperplant tray engaging with the indexing drum.

FIG. 33 is a side elevation view similar to FIG. 29 showing the ejectorpins in position to eject a row of seedlings from the upper plant tray.

FIG. 34 is a front elevation view of a first embodiment of the conveyorbelt in position below the comb assembly.

FIG. 35 is a front elevation view similar to FIG. 34 with the firstembodiment of the conveyor belt in a lowered position.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring initially to FIGS. 3, 3A and 3B, an expanded polystyrene planttray 50 similar to the tray of Todd, U.S. Pat. No. 3,667,159, as used inthe automatic transplanter of the present invention is shown. However,unlike the tray of Todd, horizontal longitudinal indexing grooves 52 areformed in the bottom surface 51 of the tray between rows of taperedpyramid shaped plant cells 54 (FIG. 15). Indexing grooves 52 have awidth equal the diameter of indexing rods 112 of an indexing drum 110(FIGS. 15 and 2A) and down loader rods 58 of down loader drums 62U and62L (FIG. 1A) and have their inner extent defined by cylindricalsurfaces 55 which mate with rods 112 and 58 (FIGS. 2 and 15). Indexinggrooves 52 comprise drive member receiving means for mechanicallypowering plant trays 50 in a vertically downward direction in a loadingframe 60 (FIG. 1) and for accurately indexing the lowermost plant tray50 to bring successive longitudinal rows R1, R2 (FIG. 3), etc. into theproper position for simultaneous ejection of all plugs from the plantcells 54 (FIG. 15) of each successive longitudinal row.

When a first plant tray 50 is placed in the upper end of loading frame60 (FIGS. 1 and 1A) it is positioned against backwall 61, FIG. 2, andmanually pushed down until it initially engages an uppermost down loaderdrum 62U. The tray 50 (FIG. 1) is positioned between a vertical frontguide flange 59F and a vertical rear guide flange 59R, as shown in FIG.2. The flanges 59R and 59F are provided on both the right and left sideframe members 60 so that the right vertical side edge 50R and the leftvertical side edge 50L of tray 50 (FIG. 3A) are each positioned betweena front flange 59F and a rear flange 59R (FIG. 2) which respectivelyengage the edge portions of the top surface 57 and the bottom surface 51of the tray 50 (FIG. 3A) so that the tray can only move downwardly.

Downloader drums 62U and 62L (FIGS. 1 and 2) are mounted to a pivotablymounted support frame 64 (FIG. 5A) pivotally attached to support frame60 by pivot sleeves 65 mounted on pivots 93 on the right and left sidesof frame 60, as shown in FIGS. 1A and 1E. Upper down loader drum 62U isbiased toward the back side of loading frame 60, as shown in FIG. 1A, bysprings 66 attached to the left and right ends of down loader drumsupport frame 64 (the left end springs being shown in FIG. 1A, and theright end springs 66 being shown in FIG. 1E).

As shown in FIG. 4, upper down loader drum 62U includes two circular endplates 70 and 72, one mid plate 74 and a central axial shaft 76. Theouter circumference of mid plate 74 is configured to match the profileof a transverse alignment groove 53, shown in FIGS. 3 and 3A, on thebottom surface of plant tray 50. Transverse alignment groove 53 isperpendicular to longitudinal indexing grooves 52 and centrally locatedon the bottom surface 51 of plant tray 50 midway between the oppositesides 50L and 50R of tray 50 (FIG. 3A). The engagement of down loaderdrum mid plate 74 (FIG. 4) with transverse alignment groove 53 (FIG. 3A)ensures that plant tray 50 is maintained in the proper position relativeto upper down loader drum 62U (FIG. 1) during the loading operation.

In a preferred embodiment of upper down loader drum 62U, as shown inFIG. 4, ten stainless steel down loader rods 58 are arranged in acircular fashion to form an open drum. One end of down loader drum shaft76 supports a sprocket 78 that is provided with a one way clutch 79 sothat shaft 76 can be driven in one direction and allowed to free wheelin the opposite direction.

Rotation of shaft 76, and therefore upper down loader drum 62U in thedirection of arrow 81, is effected by the application of air pressure tothe lower end of upper pneumatic cylinder 80U which tends to effectretraction of pneumatic cylinder 80U which tends to urge upper downloader drum 62U to rotate in the direction of arrow 81. Return spring82U and chain 84 effect rotation only of sprocket 78 in the directionopposite that of arrow 81. Chain 84 is wrapped around sprocket 78 withone end being connected to piston rod 83 of pneumatic cylinder 80U andthe other end connected to return spring 82U which has its opposite endattached to a pivotable extension arm 64a at connection point 69 (FIG.1E) to which one end of cylinder 80U and 80L (FIG. 1E) is alsoconnected. As pneumatic cylinder 80U retracts and rotates shaft 76 anddown loader drum 62U in the direction of arrow 81, return spring 82U isextended. Once the desired amount of rotation of down loader drum 62U iscomplete, pneumatic cylinder 80U exhausts and return spring 82Uretracts, keeping constant tension on chain 84. Such retraction does notexert any rotary force on down loader drum 62U due to the one way driveconnection between sprocket 78 and shaft 76.

Pneumatic cylinder 80U is pivotally mounted at its uppermost end toextension arm 64a (FIG. 1E). Extension arm 64a extends upwardly from theright side of down loader drum frame 64 as shown in FIG. 1E, and isprovided with a cylinder bracket 67 to which the uppermost end ofpneumatic cylinder 80U and spring bracket 69 is pivotally attachedproviding an adjustable connection to the uppermost end of spring 82U.The lower end of extension arm 64a is connected to down loader drumsupport frame 64 so that 64a and 64 are mounted for unitary pivotalmovement.

The chordal distance between two adjacent down loader rods 58 is equalto the linear distance between horizontal longitudinal indexing grooves52 on the bottom surface of plant tray 50. Therefore, as plant tray 50(FIG. 5) is moved into a position adjacent down loader drums 62U or 62L(FIG. 1E), down loader rods 58 (FIG. 5) engage with indexing grooves 52and thereby mechanically urge plant tray 50 (FIG. 5) downwardly when airpressure is supplied to pneumatic cylinder 80U or 80L (FIG. 1E).

Down loader drum shaft 76 is supported at each end by bearings 90, asshown in FIG. 5A, which are mounted by a quick release mechanism to downloader drum support frame 64, thereby allowing a quick and efficientchange of down loader drum 62U to accommodate plant trays havingdifferent dimensions or spacings of indexing grooves 52 (FIGS. 3 and3B).

A lower down loader drum 62L (FIG. 1A) identical to the upper downloader drum 62U is provided below drum 62U and is attached to thesupport frame in exactly the same manner as upper drum 62U.

Each down loader drum support frame 64 is pivotally mounted at its lowerright and left end by pivot sleeves 65 supported on pivot pins 93 on theloading frame 60, as shown with respect to upper most down loader drum62U in FIG. 1A and as shown with respect to upper and lower down loaderdrums 62U and 62L in FIG. 1E, and is biased towards loading frame 60 andinto engagement with the lower surface of a plant tray 50 in loadingframe 60 by a pair of springs 66 one of which engages the right end offrame 64 as shown in FIG. 1E and the other of which engages the left endof frame 64 as shown in FIG. 1A so as to bias the frame and itsassociated down loader drum to engage the bottom surface of any traypositioned adjacent the down loader drum.

Down loader drums 62U and 62L urge plant tray 50 vertically downwardinto engagement with an indexing drum 110 (FIG. 10). Indexing drum 110is formed from a plurality of parallel indexing rods 112 that arearranged in spaced parallel relationship into a drum shape and heldtogether by circular end rings 114 and 116, an interior ring 117' and amid ring 118 as shown in FIG. 8. Indexing drum 110 is supported by 8rollers 120 (4 at each end) as shown in FIGS. 6 and 7. Rollers 120engage in a machined slot 122 around the circumference of end rings 114(FIG. 8) and 116 at each end of indexing drum 110 in the manner shown inFIG. 7. Rollers 120 are attached to a quick release indexing drum frame105 which allows for quick and efficient change over of differentindexing drums 110 to accommodate different plant trays 50.

Indexing drum frame 105 comprises two parallel, substantially verticalmembers 105a which are spaced apart by a distance slightly greater thanthe total transverse length of indexing drum 110 (FIG. 2A). Thesevertical members are pivotally attached by pivot sleeves 65 at theirlower ends to main frame 60 as shown in FIG. 1A. Vertical members 105aare connected at their top ends by an upper cross member 105b' which isparallel to the central axis of indexing drum 110 and is positionedvertically above indexing drum 110 when a latch member 106, shown inFIGS. 1A and 1D, engages with a latch pin 48 attached to upper crossmember 105b' to hold indexing drum frame in position as shown in FIG. 1Afor driving engagement with plant tray 50.

Indexing drum frame 105 further comprises two annular roller supportbrackets 105c that are fixedly connected in vertical, parallel, spacedrelationship at their top ends to upper cross member 105b' and at theirlower ends to lower cross member 105b", best seen in FIG. 11. Annularroller support brackets 105c each rotatably support four rollers 120with their axes of rotation horizontal and with rollers 120 engaged inthe machined slots 122 around the circumference of end rings 114 and 116at each end of indexing drum 110, as shown in FIGS. 6 and 7.

Pneumatic cylinder support bars 105d (FIG. 1A) are fixedly connected inhorizontal, parallel, spaced relationship at the upper ends of verticalmembers 105a such that they extend perpendicular to vertical members105a and perpendicular to the central axis of indexing drum 110. Endportions 105d' of cylinder support bars 105d extend toward indexing drum110 from the opposite ends of cylinder support bars 105d and receivetherebetween a double rod pneumatic cylinder 107 at each end of indexingdrum 110.

The ends of each of the cylinder rods of pneumatic cylinder 107 areconnected to respective cylinder support bar end portions 105d', and thebody of cylinder 107 is connected by an adjustable bracket 108 to arespective end of a pin mounting beam 142 (FIG. 1B and 16). Pin mountingbeam 142 (FIG. 16) carries a plurality of plug ejector pins 144 andextends from one adjustable bracket 108 (FIG. 1A) at one end of indexingdrum 110, through the central cavity of indexing drum 110 and parallelto its central axis, and terminates at an identical adjustable bracket108 at the opposite end of indexing drum 110. Adjustable brackets 108allow for vertical and horizontal adjustments to the position of pinmounting beam 142 relative to indexing drum frame 105 and indexing drum110.

Supply of compressed air to one side or the other of cylinders 107causes the cylinder body to move either towards or away from loadingframe 60 and thereby drives pin mounting beam 142 and plug ejector pins144 (FIGS. 15 & 16) either toward or away from a plant tray 50 supportedin loading frame 60 (FIG. 1) and engaged with two indexing rods 112 ofindexing drum 110 (FIGS. 15 and 16) positioned above and below the planewithin which pin mounting beam 142 is driven.

Adjustable bracket 108 (FIG. 1B) is connected to a pinion gear supportbearing 109 that rotatably supports a pinion gear 111 (FIG. 1C) with itsrotational axis horizontal and parallel to the central axis of indexingdrum 110. Pinion gears 111 at each end of indexing drum 110 mesh withhorizontal racks 113, which are attached to annular roller supportbrackets 105c (FIGS. 1B and 1C) in spaced, parallel relationship belowpinion gears 111 to guide pinion gears 111, and therefore adjustablebrackets 108 and pin mounting beam 142 in their movement towards andaway from loading frame 60.

Pinion gears 111 are connected by a torsional shaft 168, as best seen inthe embodiment shown in FIG. 20, in order to ensure that each gearrotates the same amount and maintains the pin mounting beam 142 parallelto the central axis of indexing drum 110 throughout an entire plugejection stroke. An additional stop bar 125, shown in FIG. 1A, isfixedly connected to each vertical member 105a and positioned below andparallel to each pneumatic cylinder support bar 105d in order to providestops at each end of the path traveled by pin mounting bean 142 during acomplete plug ejection stroke.

As with the mid plate 74 of down loader drum 62 (FIG. 4), mid ring 118of indexing drum 110 has an outer circumference shaped to conform to theprofile of transverse alignment groove 53 on the lower surface of planttray 50. This configuration is shown in FIG. 9, and allows the mid ring118 to centralize and guide plant tray 50 during its downward movement.

Pneumatic locking cylinders 115, shown in FIGS. 10, 2A and 2B, aremounted on both sides of loading frame 60 (FIG. 11) at a pointvertically above the lower down loader drum 62L, and positioned toactuate press plates 117, shown in FIGS. 2A, 2B, 10 and 11, horizontallyinwardly to lock an upper plant tray 50 in fixed position at apredetermined time during its down feed past down loader drums 62U and62L. A sensor 119, shown in FIGS. 2A and 2B is mounted to look through ahole in a kick-out plate 121 positioned below indexing drum 110 as shownin FIGS. 2A and 2B. Kick out plate 121 serves the purpose of ejecting alower plant tray 50 after it has been indexed completely past indexingdrum 110 and has been completely emptied of seedlings.

Sensor 119 is positioned to detect the bottom edge 51b of lower planttray 50 when plant tray 50 has been driven downwardly to the positionwhere the second row of plant cells 54 down from the top edge 51a ofplant tray 50 is in the same horizontal plane as pin mounting beam 142and thereby positioned for ejection of the seedlings.

A signal generated by sensor 119 is sent to a processor (not shown) andtranslated into an actuation signal to pneumatic locking cylinders 115(as represented schematically by the line 123 extending from sensor 119to pneumatic locking cylinder 115 in FIGS. 2A and 2B).

The purpose of locking an upper plant tray 50 that is being drivendownwardly by down loader drum 62 at the point when a lower plant traybeing indexed downwardly by indexing drum 110 is positioned for ejectionof the second row of seedlings from the top edge of the lower tray, asshown in FIG. 2B, is to compensate for the differential spacing (causedby the requirement of an expanded polystyrene tray to have a wide outeredge to retain strength) between the top row of plant cells 177 (FIG.28) in the lower tray and the bottom row of plant cells 178 in the uppertray. The variation of this spacing from the spacing between transverserows of plant cells 178, 179 and 180 on a single plant tray would resultin a misalignment of plug ejector pins 144 with plant cells 54 (FIGS. 15and 16) if the upper plant tray were not locked in position 181 (FIG.29) from the time the lower plant tray was positioned to eject thesecond row of plants 182 until the lower plant tray had been indexed tothe last row of seedlings (top row 183, FIG. 30) then completely pastindexing drum 110 and emptied of all seedlings (FIG. 31).

The top two rows of seedlings in the lower plant tray being indexeddownwardly by indexing drum 110 are ejected by plug ejector pins 144while an upper plant tray is locked in position by locking cylinders 115in order to ensure that the upper plant tray will not be drivendownwardly by down loader drums 62U and 62L into engagement withindexing rods 112 until the lower plant tray has been completely emptiedof seedlings. The downloader drums 62U and 62L are switched off andlocking cylinders 115 prevent gravity from causing the upper plant trayto fall.

Once the lower plant tray has been indexed clear of indexing drum 110,the press plates 117 (FIGS. 2A, 2B, 10 and 11) unlock the upper planttray and the downloader drums 62U and 62L (FIG. 1A) are switched oncausing the upper tray to move downward free from obstruction in thedirection of arrow 184 (FIG. 31) and remaining clear of the indexingdrum rod 112 until the plant tray engages on indexing drum rod 112B(FIG. 32). The index drum is then indexed one position so that indexingdrum rods 112A and 112B (FIG. 33) are spaced evenly either side of thecenter line of the bottom row of plant cells in the upper tray and theejector pins 144 (FIG. 33) are on the center line of the plants to beejected.

To ensure speed and accuracy of operation during the indexing of planttray 50 (FIG. 15) in a downward direction from one row of plant cells 54to an adjacent row of plant cells, it is necessary to provide for rapidindexing of the indexing rods 112 (FIGS. 15 and 16) without skipping oroverrunning successive plug ejection positions. A means forintermittently rotating indexing drum 110 about its central axis andpositively engaging indexing drum 110 in successive plug ejectionpositions is provided by the drive pawl 138 and a special indexing lockmechanism shown in FIGS. 11, 12, 13 and 14.

Indexing drum 110 is rotated in a clockwise direction as viewed by inFIG. 11 by a drive pawl 138 driven by a pneumatic cylinder 133 that ispivotally mounted at one end to vertical frame member 105a by bracket139. Spring 131, connected between indexing drum frame 105 and drivepawl 138, biases drive pawl 138 into engagement with successive indexingrods 112 as each successive activation of pneumatic cylinder 133 resultsin clockwise rotation of indexing drum 110.

In a preferred embodiment, as shown in FIGS. 11-14, an index lock pawlmember 128 is provided having a plurality of lock lobes 130a, 130b aplurality of cam lobes 132a, 132b, a pivot opening mounted on a pivotpin 134 on fixed frame 105, as shown in FIG. 11, and an attachment point136 for attachment to pneumatic cylinder 124, which is mounted to anupwardly extending portion of frame 105. Cam lobes 132a, 132b aredisposed in between lock lobes 130a, 130b and provide a means forallowing the rotation of indexing drum 110 to assist the oscillation ofindex lock pawl member 128 generated by pneumatic cylinder 124.

Referring to FIG. 11, indexing drum 110 is positively positioned in afirst indexed position by the contact of indexing rod 112b against locklobe 130a of pawl member 128 with the resultant force being transferreddirectly through pawl member pivot pin 134 which is fixed to the supportframe 105 for indexing drum 110. Indexing drum 110 is thereby firmlypositioned in a first plug ejection position. With indexing drum 110 inthis first position, two adjacent indexing rods 112 are engaged with twoadjacent longitudinal indexing grooves 52 located on both sides of a rowof plant cells 54 on plant tray 50 (FIGS. 15 and 16). When in this firstplug ejection position, the row of plant cells 54 lie in a commonhorizontal plane with the central axis of indexing drum 110 (FIGS. 15and 16). This arrangement ensures the proper alignment of the plugejection mechanism, which is mounted to the indexing drum frame, withthe row of plant cells 54. The plug ejection mechanism includes pinmounting beam 142 that extends through the central cavity of indexingdrum 110 and carries a series of plug ejector pins 144 (FIGS. 15 and 16)for entering drain holes at the bottom of each plant cell to eject plugsand seedlings contained within each plant cell.

When indexing drum 110 is rotated about its central axis in a clockwisedirection, as shown in FIGS. 11 through 14, pawl member lock lobe 130adisengages from indexing rod 112b and cam lobe 132a rides over anadjacent indexing rod 112c, thus providing a mechanical assist topneumatic cylinder 124 which is exerting a force at attachment point 136to rotate pawl member 128 about pivot pin 134 in a clockwise directionas viewed in FIG. 12. Lock lobe 130b is thereby rotated into a positionbetween adjacent indexing rods 112e and 112f as shown in FIGS. 12 and13.

When indexing rod 112e is locked against lock lobe 130b as shown in FIG.13, indexing drum 110 is half way to the next successive plug ejectionposition of indexing drum 110 after the plug ejection position shown inFIG. 11. The rotation of indexing drum 110 to the position shown in FIG.13 is detected by a sensor 126. Sensor 126 is mounted on a bracket 127fixed to indexing drum frame 105, as shown in FIG. 11. Sensor 126generates a signal when indexing rod 112 passes close by one end of thesensor and this signal is input to a processor (not shown) which in turnsends an activation command to pneumatic cylinder 124 connected toattachment point 136 on pawl member 128. The activation of pneumaticcylinder 124 to drive pawl member 128 in a counterclockwise direction,as shown in FIG. 13, tends to disengage lock lobe 130b from indexing rod112e.

The clockwise rotational force being applied to indexing drum 110 isconveyed through cam lobe 132b as shown in FIG. 14 to assist in therotation of pawl member 128 about pivot point 134 in a counterclockwisedirection as viewed in FIG. 14. Cam lobe 132b is not free from therotational force being applied by indexing rod 112d until lock lobe 130ais fully engaged between indexing rod 112a and indexing rod 112b.Continued clockwise rotation of indexing drum 110 locks indexing rod112a against lock lobe 130a, thereby engaging indexing drum 110 in itsnext successive plug ejection position. The entire cycle is repeated toadvance indexing drum 110 to successive plug ejection positions, therebyproviding a high speed positive locking indexing method.

A rachet bar 135, shown in FIG. 11, is pivotally mounted on pivot pin134 and biased by spring 129 to engage indexing rods 112 after eachsuccessive plug ejection position is reached. Rachet bar 135 preventscounterclockwise rotation of indexing drum 110.

Because of slight variations in the lengths of plant trays 50, andtherefore the distance between cells 54, a waisted shank 144' isprovided on plug ejector pins 144 to allow for sideways deflection ofpins 144, as shown in FIG. 16. The heads of pins 144 can also beprovided with tapered spikes 145 that enter the bottom of a plug priorto it becoming dislodged from plant cell 54. Tapered spikes 145 ensurethat the plugs will not shift relative to the ejector pins 144 duringthe ejection process, and will therefore be fully ejected beforeseparating from pins 144. When pins 144 are retracted by movement of pinmounting beam 142 back away from the plant tray, tapered spikes 145easily dislodge from the plugs while leaving the plugs in their fullyejected position.

As shown in FIG. 1A and FIG. 17, a vertical plant foliage separator combassembly 170 is mounted to the front side of loading frame 60 oppositefrom indexing drum 110 and lower down loader drum 62L. Comb assembly 170separates any entangled stems and foliage enabling clear and easytransfer from plant tray 50 onto conveyer 150 in between plug retainers152. Comb assembly 170 is easily removed from loading frame 60 as amodular component by pulling pins 172 shown in FIG. 17 and removing combassembly 170 for quick and efficient changes to accommodate plant trays50 having different numbers of plant cells 54.

Angular side guides 174, shown in FIG. 21, are provided at the bottom ofindividual plates and in one preferred embodiment of the invention canbe extended the full length of 176 making up comb assembly 170 (FIG.1A). Plug retainers 152 mounted on conveyer 150 engage the base ofangular side guides 174 during the ejection of plugs from plant trays 50in order to ensure that any crooked plant stems are retained and guidedinto the correct plug retainer 152. Conveyer 150 and plug retainers 152must be moved downwardly away from angular side guides 174 beforeconveyer 150 is rotated in order to convey the plant seedlings to aplanting position. This ensures that any foliage of plant seedlings thathave been previously separated into vertical columns by comb assembly170 (FIG. 1A), but may still be partially engaged with plant seedlingsabove which could cause misalignment or damage when plant ejectionoccurs or when conveyer belt 150 is rotated, are clearly separated bythe lowering of conveyer 150. Conveyer 150 is lowered by either pivotingabout one roller 185 and lowering one end of the conveyor 186 as shownin FIGS. 34 and 35 or by the use of a parallelogram type linkage asshown in FIGS. 21 and 22.

Details of the apparatus and method for transferring seedlings alongconveyor 150 and subsequently planting the seedlings in the ground areprovided in PCT application # PCT/AU93/00408, which is hereinincorporated by reference. These details are not essential to anunderstanding of the claimed invention.

The layer of foam rubber 92 in an alternative embodiment of down loaderdrums 62U and 62L shown in FIG. 23 deforms in order to provide a nearlyconstant force at the point of contact with plant tray 50. Thedeformation of foam rubber layer 92 causes down loader drum 62U or 62Lto flatten against a number of the horizontal longitudinal indexinggrooves 52 as shown in FIG. 24. In effect, foam rubber gear teeth areformed and engaged with four or more longitudinal indexing grooves 52across the full width of plant tray 50 thereby allowing for thegeneration of a considerable down loading force on plant tray 50 whilemaintaining gentle pressure over a large area of the plant tray surface.This embodiment also allows for the accommodation of a variety of planttrays having different numbers of plant cells because of the automaticadjustment of the layer of foam rubber 92 to the spacing of longitudinalindexing grooves 52.

In another embodiment of the down loader drum, a drum 62A as shown inFIG. 25, has down loader rods 58' which are designed to be free torotate along the lower surface of plant tray 50 until they roll into andengage with indexing grooves 52. Roller bearings 94 are provided in endplates 70 and 72, and needle roller bearings 96 are fitted inside downloader rods 58' at mid plate 74. Small stub axles 98 are secured to midplate 74 to provide support for needle roller bearings 96 and downloader rods 58'. End plates 70 and 72 and mid plate 74 are secured byflanges 100 welded to the central down loader drum shaft 76. As a planttray 50 is lowered into engagement with down loader drum 62A anymisalignment between down loader rods 58' and longitudinal indexinggrooves 52 is compensated for by pivotal movement of down loader drumsupport frame 64 away from loading frame 60 as rotatable down loaderrods 58' roll along the bottom surface of plant tray 50 until they dropinto an indexing groove 52 as shown in FIGS. 26 and 27. The rollingaction of down loader rods 58' ensures that there will be no damage toplant tray 50 resulting from initial misalignment with down loader rods58'.

In one embodiment of down loader drum 62, as shown in FIG. 23, a layerof foam rubber 92 can be provided around the spaced support down loaderrods 58. The down loader rods 58 in this embodiment provide support forthe application of pressure and rotational force to the layer of foamrubber. Rotational power can be provided to the down loader drum in thisembodiment by a pneumatic powered gear drive assembly 95, rather thanthe pneumatic cylinder, spring and chain arrangement shown in FIG. 4. Inthis embodiment, a power output gear 91 driven by pneumatic powered geardrive assembly 95 engages with the ends of down loader rods 58 as shownin FIG. 5. The following description provides several additionalembodiments for plug ejection mechanisms to be mounted to the indexingdrum support frame 105 for movement relative to the indexing drum 110and along a plane that intersects the central axis of the indexing drum.However, the invention is not intended to be limited to the specificcombination of elements selected, and it is to be understood that thecombination of components described for each of the embodiments can bevaried to include all technical equivalents which operate in a similarmanner to accomplish a similar purpose.

One embodiment consists of two double rod air cylinders 140, as shown inFIG. 18, to which a pin mounting beam 142 is attached. A plurality ofplug ejector pins 144 are mounted on pin mounting beam 142. Aircylinders 140 and pin mounting beam 142 are supported on a quick releaseplug ejector frame 146. Quick release plug ejector frame 146 isdemountably fastened to indexing drum frame 105 by means such as boltingto vertical members 105a. This plug ejector sub assembly 148 can bequickly and efficiently changed in order to accommodate plant trays 50having different numbers of plant cells 54.

When plug ejector sub assembly 148 is mounted on indexing drum frame 105(FIG. 1A), pin mounting beam 142 (FIGS. 15 and 16) passes through thecentral cavity of indexing drum 110 and is parallel to the central axisof indexing drum 110. When air cylinders 140 are activated they forcepin mounting beam 142 to travel along a plane intersecting the centralaxis of indexing drum 110 and cause plug ejector pins 144 to enter thedrain holes in plant cells 54 contained in plant tray 50 as shown inFIGS. 15 and 16.

The plugs with seedlings are ejected onto a conveyer 150 having aplurality of plug retainers 152 as shown in FIGS. 21 and 22. Aircylinders 140 are then retracted and indexing drum 110 is rotated whileactivating pneumatic cylinder 124 in order to release pawl member 128(as explained in greater detail above) until the next index position isreached.

In an alternative embodiment, as shown in FIG. 19, two air cylinders 140are attached to a linear motion device consisting of a linear bearing154 that is slidably mounted on a hardened steel shaft 156. Pin mountingbeam 142 is mounted to linear bearing 154 at one end. At the oppositeend pin mounting beam 142 is connected to a polyethylene or nylon yoke158 which fits snugly but slidably around a bar 160 having asubstantially square cross section. This mechanism ensures that pinmounting beam 142 moves linearly without rotation in a planeintersecting the central axis of indexing drum 110 and the row of plantcells 54 currently positioned for plug ejection.

In another alternative embodiment of the plug ejector mechanism, asshown in FIG. 20, a gear drive 162 is mounted on quick release plugejector frame 146 to engage with two parallel gear racks 164 mounted ateach end of pin mounting beam 142. Gear drive 162 is activated by an airmotor 166 or alternative drive means. Gear drive 162 drives gear racks164 in a forward direction towards loading frame 60 and plant tray 50 inorder to eject plugs contained in plant tray 50. Subsequently, geardrive 162 drives gear racks 164 and pin mounting beam 142 backwards awayfrom loading frame 60 in order to prepare for rotating indexing drum 110to its next planting position. Torsional shaft 168 connecting the gears161 at both ends of gear drive 162 transfers equal rotational force toboth gear racks 164 and ensures that gear racks 164 remain parallel.

In describing the disclosed embodiments of the present inventionillustrated in the drawings, specific terminology is employed for thesake of clarity. However, the invention is not intended to be limited tothe specific terminology so selected, and it is to be understood thateach specific element includes all technical equivalents which operatein a similar manner to accomplish a similar purpose.

What is claimed is:
 1. A transplanter comprising:a plant tray having aplurality of cells for containing plugs of growing medium with plantsextending therefrom, said cells each having a drain hole and said cellsbeing arranged in a plurality of longitudinal rows, with said rowsseparated by longitudinally extending indexing grooves on a bottomsurface of said tray; a loading frame having a back side and a frontside for slidably supporting said plant tray for movement relative tosaid loading frame; a plurality of indexing rods arranged in spaced,parallel relationship around the circumference of a circle to form anindexing drum having an interior cavity and a central axis, with saidindexing drum being positioned relative to said loading frame to allowengagement of said indexing rods with said indexing grooves; and a plugejection mechanism positioned in the interior cavity of said indexingdrum for effecting the ejection of plugs from said plant tray that arein a longitudinal row in said plant tray in a plug ejection position;and means for intermittently rotating said indexing drum about itscentral axis for positively positioning successive longitudinal rows ofcells in successive plug ejection positions.
 2. The transplanter ofclaim 1 further including a plurality of down loader rods arranged inspaced, parallel relationship around the circumference of a circle toform a down loader drum having a central axis in a position verticallyabove said indexing drum so that said down loader rods are engageablewith said indexing grooves; andmeans for intermittently rotating saiddown loader drum so as to drive said plant tray downwardly towards saidindexing drum by engagement of successive down loader rods with saidindexing grooves.
 3. The transplanter of claim 2 wherein said indexingdrum includes a circular end ring connected at each end of said indexingrods and a circular mid ring connected at the midpoint of said indexingrods and said end rings and mid ring being perpendicular to saidindexing rods and concentric to the central axis of said indexingdrum;said plant tray having an alignment groove in the bottom surface,with said alignment groove being perpendicular to said indexing groovesand having a profile configured to mate with an outer circumference ofsaid circular mid ring, thereby providing means for positioning saidplant tray relative to said indexing drum and said plug ejectionmechanism.
 4. The transplanter of claim 3 wherein said plug ejectionmechanism comprises a plurality of plug ejecting pins, a pin mountingbeam supporting said pins in a row in said interior cavity of theindexing drum and with said pins each being spaced apart a distancesubstantially equal to the distance between the drain holes in saidcells and power actuated means for unitarily moving said pins toward alongitudinal row of cells in said plug ejection position for ejectingplugs from said row.
 5. A transplanter for positioning plant trayshaving drive member receiving means in successive positions forsimultaneous ejection of a row of plant seedlings contained within saidplant trays and ejecting said seedlings, said transplanter comprising:aloading frame for supporting a plurality of vertically stacked planttrays including an upper plant tray adjacently above a lowermost planttray with said seedlings being oriented in vertically spaced horizontalrows of said plant trays; a plurality of plant tray drive members; meansmounting said plant tray drive members for movement relative to saidloading frame; means moving said plant tray drive members intoengagement with said drive member receiving means for moving said planttrays in an infeed direction having a vertical component; means forserially ejecting rows of seedlings row by row from the verticallyspaced horizontal rows of the lowermost plant tray with said means forejecting being mounted in a lower drive member engaged with and adjacentsaid lowermost plant tray for movement relative to said lower drivemember for ejecting a row of seedlings from said lowermost plant tray;and means for clamping the upper plant tray positioned adjacently abovethe lowermost plant tray in a fixed position relative to said loadingframe while the lowermost plant tray is being moved in said infeeddirection by one of said plant tray drive members.
 6. The transplanteras recited in claim 5 wherein said drive members are provided on ahollow indexing drum and said means for ejecting seedlings is mountedinternally of said hollow indexing drum.